Ice resurfacing blade

ABSTRACT

A blade is made of a heat-treat-able and corrosion resistant steel, preferably 440C stainless, that has one or two sharp edges for resurfacing ice, such as at an ice rink with an ice resurfacing machine, such as a Zamboni® resurfacing machine. It uses at least one attached mounting bolt; and may have a removable safety cover mounted to it. The method of producing the blade includes: selecting a corrosion resistant metal; forming it to have one or two sharp edges; defining a receiver hole for receiving a threaded mounting bolt; heat-treating to a hardness of about 55; machining; and securing a mounting bolt through the blade to align with a mounting location. The blade may contain stiffening inserts. The blade may contain a bushing to secure and precisely locate the mounting bolt.

CROSS REFERENCE TO RELATED APPLICATION

This application is a continuation in part of co-pending U.S. patent application Ser. No. 10/272,746, filed on Oct. 16, 2002, which claims the benefit of U.S. Provisional Application No. 60/329,940, filed Oct. 17, 2001. Applicant requests that the Disclosure Document Number 495874, filed at the United States Patent and Trademark Office on Jun. 18, 2001 be associated with this application.

FIELD OF THE INVENTION

This invention relates to a device for smoothing ice when mounted on an ice resurfacing machine.

BACKGROUND OF THE INVENTION

Since the introduction of the first ice resurfacing machine in the 1940s by Frank Zamboni, the technology has changed little. He experimented with machines that would shave, scrape, wash and squeegee the skating rink ice surface before putting down a fresh layer of water. Today, perhaps the best known of these are the Zamboni® and the Olympia® ice resurfacing machines. Zamboni® is a registered trademark of Frank J. Zamboni & Co., Inc. Olympia® is the registered trademark of Leclair Equipment Ltd. Such a machine employs a large metal blade which scrapes the surface of the ice a precise amount in order to provide an ice surface which is free of defects and which can be left smooth by the introduction of a thin layer of water, which promptly freezes into a new, smooth ice surface.

With use, an ice rink eventually becomes rough and pitted plus dust and dirt particles dull it. The ability to quickly and effectively resurface the ice is important to skating and to the development of artificial ice rinks. Before ice resurfacing machines, ice surfaces were maintained manually, using scrapers, towels, a water hose and squeegees. Resurfacing a regulation size rink was time-consuming and labor intensive.

Ice resurfacing machines cost about $60,000 and are mass-produced. Every ice rink has at least one. Professional hockey teams typically use two machines to cut down on the time needed to resurface the ice between periods.

In hockey, the ice is resurfaced before the game, after warm-ups, between periods, and when the game is over. With two resurfacing machines, it takes three minutes to complete the floor.

The blade scrapes a 1/16-inch to ⅛-inch layer of ice from the ice surface. The blade is as wide as the machine and looks like a very large razor blade with one sharp edge. The amount of ice taken off depends on the ice conditions. The rougher the surface becomes with use, then the deeper the blade must cut.

Olympia ice resurfacing machines have a carbon steel, 84-inch long, ½-inch thick blade and most Zamboni ice resurfacing machines have a 77-inch long, ½-inch thick blade. The metal blades are typically about 6-inches wide. The blades are attached to the ice resurfacing machine by means of numerous removable bolts, typically ten or more.

The blades must frequently be sharpened, which requires removal from their mounted position under the resurfacing machine. The old blade is usually replaced immediately with a new sharp blade. The procedure is labor intensive and costly. Ice rinks lose business if the quality of the ice surface is not maintained in a smooth state, thus requiring frequent use of the resurfacing machine.

The replacement procedure is dangerous because each blade weighs about 50 pounds and has one sharp edge. The blade can easily sever a finger, foot or hand, if it falls. The blade is most dangerous during replacement when the worker must reach under the machine and install ten or more bolts to secure the blade in place. Further, used blades and replacement blades must be stored at the ice rink.

Used blades are usually re-sharpened. Because of the size of the blade and the requirement that the blade be very straight and very sharp, sharpening is done by a machine shop. This requires that the blades be shipped to the machine shop and returned to the ice rink after sharpening.

Conventional blades have a limited life before they are scrapped because each sharpening procedure removes metal from the edge of the blade, thereby reducing its width.

The blades also corrode from exposure to the wet environment of an ice rink. Rust shortens the life of the blade and creates an undesirable staining of both the blade and anything that it comes in contact with, such as the ice rink floor or the technician that replaces the worn blade. The machinist must clean the excess rust from the blade before it can be sharpened.

The blades must be carefully adjusted during use to avoid making too deep of a resurfacing cut. A cut as deep as ⅜-inch will destroy the blade, perhaps requiring it to be scrapped, if not removed and re-sharpened. Further, the blades are easily damaged if they strike a hard object, such as a metal threshold at the ice rink entry.

If the blade is not damaged, thereby shortening its useful life, then its normal life is typically about 15 months, after which it must be scrapped. It is normal that a blade will be removed from the resurfacing machine and sharpened twice per week.

These problems are known in the resurfacing industry and numerous attempts to find better blades have been attempted. Efforts to use stainless steel failed when it was found that the blades did not hold a sharp edge for as long as conventional 1018 carbon steel blades. Efforts to heat-treat stainless steels resulted in dimensional changes rendering the blades useless, since they could not be attached to the resurfacing machines, which have a mounting hole tolerance of 0.030-inches of center.

Efforts to increase blade life led to surface treatment, such as carbide or nitride surface treatment. These treatments increased the initial blade life, but when the blade was sharpened, the surface treatment was removed. Brazing of a thin hard material surface layer was also attempted, these “sandwich braze” efforts failed when the surface layer peeled off.

There is a need for an improved blade with longer life and lower maintenance requirements that will allow ice machines to work the ice more quickly.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a perspective view of the blade and safety cover.

FIG. 2 depicts a perspective view of the back of the blade.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

An ice resurfacing blade 10 illustrated in FIG. 1 is configured to be mounted to a conventional ice-resurfacing machine. In a preferred embodiment, the ice resurfacing blade 10 is comprised of a corrosion resistant and heat-treatable metal that is as about 60 to 96-inches long and weighs between about 55 pounds for a ½-inch thick blade and 70 pounds for a ⅝-inch thick blade. The preferred material is stainless steel, such as 440C. Alternative steels include 17-4 ph stainless, 15-5 ph stainless, 13-8 ph stainless, 410 stainless, and 420 stainless. These materials are less advantageous since they are not heat-treatable to the extent of the preferred 440C stainless.

Alternative embodiments include blades 10 that are comprised of other corrosion resistant materials, such as ceramics, including but not limited to, alumina, transformation toughened alumina, transformation toughened zirconia, carbides, nitrides, or refractory materials, such as but not limited to tungsten carbide, tungsten nitride, nitrided steel, and refractory metals, including tungsten, molybdenum, and niobium. The blade 10 may be a composite blade that includes inserts of these materials in a mounting plate, where the corrosion resistant material forms a part of the sharp first use edge 12 or second use edge 14, that retain their sharpness after prolonged use. An alternate approach to providing a lightweight but stiff blade 10 is to provide stiffening inserts 6, which in a preferred embodiment are filled with a high elastic modulus material thus forming a structure that increases the overall stiffness of the blade.

A further alternative embodiment utilizes coatings of hard, corrosion resistant materials, such as ceramic or refractory metals, on the blade 10 so as to enable the blade edge 12 and edge 14 to maintain a sharp edge for prolonged use. Examples of ceramic coatings include, for example, diamond, diamond like carbon, and ultra-nanocrystalline diamond.

It is desired that the blade 10 not be so hard that it may fail in a brittle manner during use. It is also desirable that the blade 10 be capable of being machined to sharpen the edge of first use 12 and, if a double-edge blade, the edge of second use 14 that is located on the opposite edge of the blade. An alternative embodiment has the edges 12 and 14 on different faces, for example, first use edge 12 is on front surface of blade 30 and second use edge 14 is on back surface of blade 42. This is not preferred for safety reasons, since in a preferred embodiment both edges 12 and 14 are protected with one safety cover 20.

In a preferred embodiment, the blade 10 is machined to the approximate final dimensions, including placing the sharp edges 10 and 12 at a known blade angle 16 that is preferably approximately 30°. The blade angle of known carbon blades is about 24.5°. In alternative embodiments, the blade angle 16 may vary between about 15° and 65°.

It is also preferred to machine receiver holes 32 each containing a receiver hole step 34 before heat-treatment. In a preferred embodiment there are approximately 10 holes that are placed along the long axis of blade 10 and approximately in the middle of the width of blade 10 so as to align with the required configuration of the ice resurfacing machine. Each hole 32 is identical to the other.

A bushing 18 is placed in each receiver hole 32 after heat-treatment and machining of the blade 10. Preferably, conventional grinding operations are performed to result in a straight blade 10 and parallel edges 12 and 14. A preferred material for the bushing 18 is 303 stainless steel. The bushing 18 contains a bushing reduction 24 that when pressed into receiver hole 32 bottoms out on receiver hole step 34, thereby securely fixing the bushing 18 in the holes 32. The bushings 18 are machined flat to the front surface 30 and to the back surface 42 of blade 10. A series of holes 22 are placed at precise locations so as to align with the required mounting holes in the resurfacing machine. The holes 22 may be through holes with no threading, but in a preferred embodiment each hole 22 is threaded to receive a mounting bolt 40. In this preferred manner the mounting bolt 40 emerges from the back surface 42 as a threaded stud, as shown in FIG. 2. Rather than each bolt 40 having to be placed and mounted individually with a separate nut, as is conventionally done while the blade dangles under the resurfacing machine, in this improvement, each mounting bolt 40 is ready to receive a nut after the blade is initially placed in position. In an alternative embodiment, mounting bolt 40 is not threaded, but is attached to a resurfacing machine by means such as pins placed though holes in the bolts 40 that emerge from blade 10.

The back surface 42 of blade 10 is illustrated in FIG. 2 with the threaded mounting bolts 40, which are securely fastened to the blade 10 by means of the threaded bushing 18, emerging from bushing 18. The bushing reduction 24 is machined flat with back surface 42 of blade 10.

After the blade 10 is heat-treated, final machining is performed to place straight sharp edge of first use 12 and straight edge of second use 14 parallel to the longitudinal axis of the blade 10 and parallel to each other to assure proper orientation with respect to the system of mounting bolts. The heat-treatment is preferably accomplished to result in an extremely hard material having a preferred hardness of about 55 to 60 Rockwell C when the blade 10 material is 440C stainless.

To achieve extra rigidity in blade 10, an alternative embodiment, not illustrated, is to honeycomb the front surface 32 and/or the back surface 42 of the blade 10. This stiffens the blade without increasing the weight. Stiffening inserts 6 which also stiffen the blade are illustrated in FIG. 2. The resulting blade stiffness leads to reduced vibration helps to insure that the machined ice surface is smooth and ripple free.

A safety cover 20, illustrated in FIG. 1, is a preferred embodiment wherein the safety cover 20 has dimensions that are approximately equal to the length and width of front surface 30. The safety cover 20 is preferably made of a lightweight material, such as aluminum, but may be comprised of any strong material, such as wood or metal. The safety cover 20 is held in place during shipping, storage, handling, and placement by safety cover bolts 44, preferably one at each end of safety cover 20. The safety cover through holes 46 are not threaded and are aligned with the threaded holes 36 in the front surface 32. Safety cover bolts 44 are securedly attached into safety cover mounting holes 36. It is preferred that the safety cover 20 remains in place on blade 20 until blade 20 is mounted and secured to the resurfacing machine.

Obviously, many modifications and variations of the present invention are possible in light of the above teachings. It is therefore to be understood that, within the scope of the appended claims, the invention may be practiced otherwise than as specifically described. 

1. An ice resurfacing blade that is adapted for mounting to a resurfacing machine, wherein: said blade is comprised of a metal that is corrosion resistant and heat-treatable; said blade comprises at least one straight and sharp first edge; and a means for mounting said blade to the machine.
 2. The blade according to claim 1, wherein said means for mounting is at least one threaded stud that is attached to said blade.
 3. The blade according to claim 1, wherein said blade is comprised of 440C stainless steel.
 4. The blade according to claim 1, wherein said blade is comprised of a refractory metal.
 5. The blade according to claim 1, wherein said corrosion resistant metal is heat-treated to a hardness of about 55 to 60 on the Rockwell C scale.
 6. The blade according to claim 1, wherein said blade is comprised of stiffening inserts.
 7. The blade according to claim 1, wherein said blade is comprised of a second use edge that is oriented opposite said first use edge.
 8. The blade according to claim 7, wherein said blade has a front surface and said first use edge and said second use edge are oriented on said front surface.
 9. The blade according to claim 1, wherein said blade further is comprised of a safety cover that is removably mounted to said blade to enable cover removal after said blade is mounted to the resurfacing machine.
 10. The blade according to claim 1, wherein said blade weighs less than about 90 pounds.
 11. The blade according to claim 1, wherein said blade has a length between about 60 and 96 inches.
 12. The blade according to claim 1, wherein said blade has a blade angle between 15 and 65 degrees.
 13. An ice resurfacing blade for that is adapted for mounting to a resurfacing machine comprising: a corrosion resistant, heat-treatable metal; at least one stud that is affixed to said blade; and a first use edge and a second use edge both of which are straight and sharp.
 14. The blade according to claim 13, wherein said metal is 440C stainless steel.
 15. The blade according to claim 13, wherein said blade has a front surface, said first use edge and said second use edge located on said front surface.
 16. A method of producing an ice resurfacing blade, comprising the steps of: providing said blade comprised of corrosion resistant metal; forming said blade to have at least one edge that is straight and sharp; forming said blade to define at least one hole for receiving a threaded mounting stud; heat-treating said blade to a hardness of about 55 to 60 on the Rockwell C scale; sharpening said edge after said heat-treating step; and securing said stud to align said blade with a predefined mounting location.
 17. The method of claim 16, further comprising placing a bushing in said blade for receiving said mounting stud.
 18. The method of claim 16, wherein said step of forming said blade is forming two straight and sharp edges.
 19. The method of claim 16, wherein said step of providing said blade further comprises providing a blade comprised of 440C stainless steel.
 20. The method of claim 16 further comprising removably mounting a safety cover to said blade. 